Friction shock-absorbing device



Spt. l5, 1936. L KURTSSY 2,054,329

FRICTION' sHocx ABsoRBING DEVICE F'iledNov. 21, 1935 2 sheets-sneezePatented Sept. 15, 1936 UNITED STATES PATENT oFFicE Application November21, 1935, Serial No. 50,877 In Germany November 1, 1934 9 Claims.

The present invention concerns a device in which the kinetic energy ofmoving masses is intercepted or annihilated with the aid of relativelylow spring forces, by using friction faces.

; In the already known devices of this kind, either the friction facesbear such high pressures per surface unit that they must be permanentlygreased, so as to avoid jamming of the faces, or there is the drawbackthat even with a friction coeiiicient augmenting but a little, thedevicesafter bufling-do not return into their original position, or elsethey jam while bufling, i. e. during the working stroke; the presentinvention is intended to eliminate all these disadvantages, whilerequiring a minimum of space.

Some devices are known, in which this is obtained by a certaindisposition of the friction faces and spring, whereby the bufiingplates, which approach mutually under draft or buifing forces, have ontheir inner side a depression formed by faces placed obliquely to thebufng direction, while friction blocks are placed between these obliquefaces of the depression, these blocks approaching mutually under buffingstrains, perpendicularly to the bufling direction and against the actionof a spring. The device obtained with this disposition is useful forsmall work only, while its dimensions must be small; however, it doesnot jam, even if the friction coeiiicient `augments considerablyAccording to the present invention, this disposition presents the simplepossibility of a rapid increase of the ratio: buing force to springforce, and thereby also of the power of the device, be-

cause the mutual disposition of the spring and friction faces permits toencase several friction elements one into the other, with a singleinside-acting spring. The ratio can thus be potentiated in such a waythat it augments according to the succession rc, m2, ac3 etc, contraryto the already known devices, where the ratio-with a device repeatedseveral times-augments according to the succession 2x, 3a: etc.'I'herefore the repetition of the device forming the object of thepresent invention does not represent a simple juxtaposition of elementssimilar in form and dimensions, but an encasing in similar but biggerelements which enclose the smaller Ones.

A model execution is shown in the following drawings:

Figs. l, 6, '7, 8, 9, and 10 are horizontal sections,

Figs. 2 and 1l are side view and vertical section corresponding to Figs.l and 10 respectively;

Fig. 3 shows the paralleogram of forces corre-VV sponding to Fig. l,without friction;

Fig. 4 shows the same under friction, during the working stroke of thedevice. Y y

Fig. 5 is a similar diagram of the backstroke of the device.

The plan can also be considered as side view; in this case, the sideview must naturally be considered as plan. As the parts generally fixedto the car, such as guides, draft links, which enable 1o the same deviceto transmit also draft strains, etc., do not belong to the object of thepresent invention, they are not shownV in the drawings.

Figs. 1 and 2 show a disposition in which one pair of friction blocks isutilized. The buiiing 15 plates IA and IB, fixed between the stopsl onthe underframe of the car, are mobile in the direction of the forces P,-P;. on their inner sides are depressions formed by the oblique faces 2,3. The friction blocks IC, ID, placed between these 20 oblique faces,being held separated by a spring 4, approachmutually during the bufling`stroke of the bufng plates. If the force P or -P ceases to act, thespring pushes the two blocks IC, ID and thereby also the buing platesIA, vIB back into 25 their original extended position.

By reason of the friction acting upon the faces 2, 3 during themovements of the device, part of the Work of the force P whilecompressing, and part of the work of the spring while ex- 30 tending, istransformed into friction work. Consequently, on one hand a smallerspring force R can be utilized, and on the other hand the undesirablereaction force P of the already small spring is further reduced. 35

Fig. 3 shows the parallelogram of forces, in the case of p=tg=0, i.,e.if there is supposed to be no friction; Fig. 4 shows the parallelogramof forces during compression, i. e. during the working stroke, if ii=tgis the friction coefficient on the friction faces. Fig. 4 shows thatduring the working stroke, the counter force R', being opposite toV thepressure force P', and counter-balancing the latter, becomes equal to 0if (=90a); in other words: with this friction coeiiicient, no springforce is necessary to balance a pressure force of any amount ofimportance. This is the case if, during the pressure stroke, the devicebecomes 50 self-locking, i. e. gets jammed. From the above, therefollows that 245 gives the maximum safety as regards the requirementthat no jam ming shall occur during the working stroke and the backstroke. In the case of =45., jamming 55 would only occur with a mostunlikely friction coeflicient of c=tg 45=1.

The proportional number P', R' shows what a big ratio has been achievedby using the friction faces during the working stroke, the bigger thisproportional number is in a device, the smaller a spring force sufficesto obtain a given big amount of working capacity.

Fig. 4 shows furthermore that the ratio P', R', during the Workingstroke is of better advantage, i. e. bigger if a is smaller.

Fig. 5 shows the ratio during the back stroke, the forces P", R" beingsimilar in effect but opposite to the forces P', R' of Fig. 4.

After due consideration of these contrary'conditions as well as of therequirements concerning jamming, it is found that the best results areobtained with an angle a lying between 30 and 40.

Figs. 6 andy 7 show the way in which the principle of Fig. 1 may beapplied two times, in view of augmenting thel ratio P, R, i. e. toincrease a second timeY the spring force. The inner oblique faces of thefriction blocks IC, ID are also executed as friction faces, and anotherset of inner friction blocks 2A, 2B is encased between them. Instead ofthe spring 4, a spring 5 is inserted between these inner frictionblocks.

If, in this case, the angle a of Fig. 1 is called 1 and thecorresponding angle of the second step a2, that which has been saidbefore on the subject of jamming and ratio now also concerns this secondstep; the outer friction blocks IC, ID correspond tothe bufling platesIA, IB and the inner friction blocks 2A, 2B correspond to the frictionblocks `ICLID. n

Therefore this second step orV inner disposition keeps al1 the featuresof the outer step and shows no new ones. If for example the outerdispositionk was not self-locking, the inner disposition shows the samesafety against jamming, supposing naturally that 2l-1:11. I f forexample, in the execution according to Fig. 1, the ratio P, R amountedto '.fr, the same vratio also exists in the inner disposition, naturallyalways supposing that a2=a1=a- Therefore, the ratio of the two-steppeddisposition amounts to r2, as compared to the ratio 9: of theone-stepped disposition.

This is a differencein comparison to the other known devices, inwhich--when the disposition is repeated twice-the ratio is only of 2x.'

' Figs. 6 and '7 are drawn according to the condition'a2=a1=a, with thedifference that in Fig. 7 a may be any angle, and in Fig. 6 (1:45". Invview of obtaining the ratioP, R for the disposition shown in Fig. 6, thesubdivision accordingv to Fig. 4, 5 would have to be continued in thegiven sense.. Y

As the ratio augmentswith they double execution, the initial amount ofthe bufiing forcewhich corresponds to the initial tension of the springS-augments as well. Inorder that it may Y not become too important, apreliminary spring In Figs. 1 and 6, the spring is placed on the insideof the friction elements, in Figs. 7, 8, and on the outside, but in thelatter case their action is the same, by the insertion of a rodding.

When executed as shown in Fig. 7 for example, this rodding consists of atube 9, the two extremities of whichY are bearing the spring plates I9,II. The outer ends of the springs I2, I3 act upon the spring plates I4,I5. The bars I5, Il forming one. body with these spring plates, possessT-shaped heads which pass through the slot I8 of the tube 9 and act uponthe friction blocks 2A, 2B.

In the execution according to Fig. 8, this rodcling distinguishes itselffrom that of Fig. '7 in that the friction blocks 2A, 2B are actuated bythe inner ends of the springs 2I, 22 with the aid of a bar I9 and tubecharged with the pressure and not with the traction force. At the sametime, the outer ends of the springs 2 I 2,2 act as preliminary springswhich push back the buffing plates IA, IB into theirV extendedpositions, after bufling is terminated.

If the device according to Fig. 1 or Fig. 6 is executed two times, threetimes, consecutively, in the direction of the bufling force, Fig. 9,this disposition presents the double, treble, stroke, while the startingand terminating values of the bufiing force remain the same.

If the two devices according to Fig. 9 are executed in such a Way thatthe bufiing plates IA and IA", iB, and IB" respectively form one piece,this disposition presents the double cf the bufng .forces in comparisonto the execution according to Fig. ,1., while the stroke remains thesame.

Instead of doubling the principle shown inv Fig. 1, it may also beapplied three or'four times. This latter case is shown in Figs. 10 and11. The friction blocks 3C, 3D and 4A, 4B are added to the frictionblocks of the double execution. The force of the spring 24 acts upon thefriction blocks sb.- A

A, 4B, because the left and right endsof the spring, with the aid of thespring plates25 and 26Vand bars 2l, 28, move the friction blocks 4A andVcoupler and the pressure bar into their original position with enoughforce, auxiliary springs 3l are inserted between the plates 29, 30 whichare in connection with the buing plates IA, IB. These auxiliary springs3| continually tend to separate the two bodies IA, IB, and the spring24, while' extending, has only to place back the friction bodiesinto'their original positions.

With this quadruple execution, the ratio amounts to r4 as compared tothe ratio n: of the execution shown in Fig. l, presuming that theObliquity of the slanting faces remains the same.

With a treble execution,'the friction blocks 4A, 4B are eliminated, andthe spring acts directly upon the friction blocks 3C, 3D,perpendicularly to the direction of the force P. With this execution,the ratio amounts to x3' as compared to the ratio r of the executionshown in Fig. 1, presuming that the Obliquity of the slanting facesremains the same.

What I claim is:

l. Shock-absorbing friction device, comprising bufing plates, adapted tomutually approach under draft or bufng strains, each having on its innerside a depression formed by faces placed obliquely to the direction ofthe bufiing strains, two friction blocks placed between these obliquefaces, each friction block having on its inner side a depression formedby faces placed obliquely to the direction of the movement of theblocks, and two other friction blocks inserted between thelast-mentioned oblique faces, and rodding operatively connected with theinner friction blocks and extending outwardly relative to an end of atleast one of said inner friction blocks and having resilient meansconnected therewith counteracting the movements of the inner frictionblocks.

2. Shock-absorbing friction device according to claim l, characterizedby the feature that according to the principle described furtherfriction blocks are encased into one another, in the inner frictionblocks of the device and instead of the aforementioned resilient meansthe inmost pair is held separated by a spring.

3. Shock-absorbing friction device according to claim 1, characterizedby the feature that the rodding is executed symmetrically and that twosprings act upon the inmost friction blocks.

4. Shock-absorbing friction device according to claim 1, characterizedby the feature that the device is connected in series with a preliminaryspring which has such an initial tension that it begins to act beforethe shock-absorbing friction device properly speaking begins to work.

5. Shock-absorbing friction device according to claim 1, characterizedby the feature that a preliminary spring is connected in series with thedevice and the spring acting upon the inmost friction blocks begins towork together with the preliminary spring, before the shock-absorbingfriction device properly speaking begins to work.

6. Shock-absorbing friction device according to claim 1, characterizedby the feature that auxiliary springs are inserted between the firstpair of leuning plates, which act upon the further friction blocks,these auxiliary springs excluding the possibility of self-jamming.

7.' In a shock-absorbing friction device, the combination of buiiingplates each having converging inner faces, friction blocks interposedbetween the bui-ling plates and having aring sides contacting the innerfaces thereof, said friction blocks each having converging inner faces,inner friction blocks having Wedge-shaped end portions engaging theinner faces of the first-mentioned friction blocks and movable inwardlytoward each other from said inner faces, rodding having means connectedtherewith for operating on the inner friction blocks, and resilientmeans bearing in opposite directions on different portions of theredding for counteracting movement of the friction blocks.

8. In a shock-absorbing friction device, the combination of bufng plateseach having converging inner faces, friction blocks interposed betweenthe bufng plates and having aring sides contacting the inner facesthereof, said friction blocks each having converging inner faces, innerfriction blocks having wedge-shaped end portions engaging the innerfaces of the first-mentioned friction blocks and movable inwardly towardeach other from said inner faces, telescoped rodding having meansconnected therewith for operating on the inner friction blocks, saidrodding projecting externally of the space between the firstmentionedfriction blocks, and resilient means externally of said space andbearing in opposite directions on ldifferent portions of the rodding forcounteracting movement of the friction blocks.

9. Shockfabsorbing friction device according to claim 1, characterizedby a plurality of pairs of inner and outer friction blocks locatedbetween the buing plates, and connected with the rodding, one pair ofinner and outer friction blocks being located within the other pairthereof in series.

LszL KRTssY.

